How many different 4-letter words can be formed with the letters of the word 'JAIPUR' when A and I are always to be included?

Options

A. 24
B. 4
C. 20
D. 144

Answer

D

Explanation

Since A and I are always to be included, so first we select 2 letters from the remaining 4, which can be done in ` ""^(4)C_(2) = 6` ways. Now these 4 letters can arranged `4! = 24` ways, so the required
number ` " " `= 6 x 24 =144 ` " " ` Ans. [4]